fix: no graph generated, when grafanaimagefiltersarray not set

Author: fabianbees

library/Grafana/ProvidedHook/Icingadb/IcingaDbGrapher.php

@@ -485,7 +485,10 @@ public function getPreviewHtml(Model $object, $report = false): ValidHtml
                 $i++;
             }
 
-            foreach ($info as $value) {
+            $i = 0;
+            do {
+                $value = $info ? $info[$i] : "";
+
                 // The image value will be returned as reference
                 $previewHtml = new HtmlDocument();
                 $res = $this->getMyPreviewHtml($serviceName, $hostName, $previewHtml, $value);
@@ -503,6 +506,8 @@ public function getPreviewHtml(Model $object, $report = false): ValidHtml
 
                     $html->addHtml($previewHtml);
                 }
+                $i++;
+            } while ($i < count($info));
 
             $returnHtml->add($html);
         }